Hi All,

There is a post further below titled "tachometer/mpg not working.....please help 86 528e". Well I have been having the same problem. Dave, at the bottom of that thread, says something about a rectangular plug.

I was looking for the plug he is talking about but it is a bit difficult to know exactly which he is talking about without a picture. In my 88 535is E28, in the glove box there are two "Black Boxes".

They are mounted more or less on top of each other. The top box has its connector in the front (facing me) aligned with the lateral axis of the car, i.e., side to side. The bottom box has its connector inboard and aligned with the longitudonal axis of the car, i.e., front to back.

I believe the bottom box is the ECU/DME, and the top box I have no idea. I disconected the top one while the engine ran and there was no change. Could this be the rectangular plug he is talking about? Does this top box control the MPG and Tach? If it is this could be a break through!

Before anybody says anything, I have already checked my SI board and batteries. They are good.